Conventionally, coating materials mainly containing a melamine resin such as alkyd melamine or acrylic melamine have been used for coating automobiles, industrial equipments, steel furnitures, interior and exterior of buildings, household electric appliances, plastics and the like.
However, these coating materials mainly containing a melamine resin involve the problems that harmful formalin greatly generates during curing and that cured coating films are damaged by acid rain because they are poor in acid resistance. In particular, the problem of acid rain owing to air pollution assumes a serious aspect in recent years, and there is observed a phenomenon that etching, whitening or spotting occurs in the coating films.
As a curable composition suitable as a coat, which solves the above-mentioned problems, there are known a curable coating composition containing a blend of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol, and a curable coating composition containing a copolymer of a vinyl monomer having a hydrolyzable silyl group and a vinyl monomer having an alcoholic hydroxyl group (Japanese Unexamined Patent Publication No. 141952/1989 and Japanese Unexamined Patent Publication No. 136324/1994).
However, the above-mentioned curable coating compositions are demanded to improve easiness in removal of adhered stains, namely stain resistance, from the viewpoints of beauty of appearance, easiness in cleaning, decrease in the number of cleaning operations and the like.
The present invention has been accomplished in consideration of the above-mentioned prior art, and aims at providing a curable composition suitable as a top coat showing an excellent stain resistance in addition to excellent acid resistance, scratch resistance, water resistance and thermosetting property, and a coated material using it.